Rendering cellulosic articles antimicrobial through treatment with quaternary ammonium compounds having a reactive methylolamide group



United States Patent US. Cl. 8116.2 2 Claims This invention relates to the treatment of cellulosic articles, such as fabrics, with certain quaternary ammonium compounds to obtain antimicrobial and other effects resistant to destruction through rinsing or washing. More particularly, this invention relates to a treatment of cellulosic materials for protection against rotting, for the prevention of growth of micro-organisms thereon, and softening effects.

Permanent treatment of cellulosic materials to render them resistant to or immune from biotic attack is obviously advantageous. Tent canvas, awnings, and tarpaulins would benefit markedly from an eifective rot-proofing treatment. Clothing in tropical climates, bedding, and diapers are but a few of the possible applications for a cotton fiber rendered bacteriostatic.

Long chain quaternary ammonium compounds are firmly established as textile adjuncts. Their use as fabric softeners is well known. The use of certain long chain quaternary ammonium compounds as biocides is also well known. Formulations combining fabric softening and biocidal activity are currently available. However, experience has taught that conventional treatments which give softening and resistance to biotic attack are merely temporary. Rinsing or washing of the treated fabric has been shown to exhaust the active compounds. The and microbial properties of the conventionally treated cloth are particularly susceptible to rinsing or washing so that most of the antimicrobial eifect disappears. This suggests that in treatment with a long chain quaternary ammonium compound, a certain part is relatively firmly bound to the cellulosic fiber, whereas the remainder is more or less loosely deposited on the fiber itself. This loosely bound material is relatively easily removed by rinsing. Treatment of cellulosic fabrics with long chain quaternary ammonium compounds has heretofore been unsuccessful with regard to the attainment of any degree of permanency of anti-microbial and/ or softening activity.

It is an object, therefore, of the present invention to provide long chain quaternary ammonium compounds exhibiting antimicrobial and/or softening activity when used to treat cellulosic fabrics, particularly cotton.

It is a further object of the present invention to provide long chain quaternary ammonium compounds, the anti-microbial and/or softening effect of which, when absorbed on a cellulosic fabric is more or less permanent, that is resistant to further rinsing and/ or washing.

Other objects and advantages of the present invention will appear in the discussion and examples that follow.

We have now discovered that the treatment of cellulosic fabric, particulary cotton, with a compound of the general class of the aldehyde reaction products of long chain quaternary ammonium compounds containing amide groups with available active hydrogens results in the attainment of the objects of our invention. These alkylol derivatives (formed from the reaction of an aldehyde with the amide group) provide a chemical linkage for permanently bonding the entire molecule to the cellulosic fabric. This chemical linkage, in contrast to the conventional physico-electrical bondings of a conventional quaternary ammonium compound, is highly resistant to rinsing and washing and is of a more or less permanent nature. Cellulosic fabrics treated with compounds of this type exhibit a high degree of anti-microbial and/or softening activity, which is relatively permanent.

A variety of quaternary ammonium compounds have been found to be applicable to our present invention. The only limitations placed upon compounds coming within the scope of our invention are of a fundamental nature. To be operable within the concept of our present invention, a compound must have (1) at least one long chain aliphatic hydrocarbon radical of the type generally associated with biocidal activity, (2) at least one quaternary ammonium nitrogen atom, and (3) at least one carboxylic acid amide grouping, unsubstituted or monosubstituted, reacted further with an aldehyde to provide an alkylol grouping. A variety of quaternary ammonium compounds fulfilling the above three criteria and subsequentlyreacted with aldehydes to produce an alkylol derivative have been shown to be effective within the scope of our present invention.

The compounds of the present invention, therefore, may be represented by the following general formula:

where R is an aliphatic hydrocarbon radical of from 4 to 24 carbon atoms, Q contains at least one quaternary ammonium nitrogen atom carrying a positive charge, R is a divalent alkylene radical of from one to 14 carbon atoms, R" may be hydrogen or an alkyl radical of from one to 24 carbon atoms, R is from one to four carbon atoms or hydrogen, and X is a salt forming anion. Included in Q may be other aliphatic or cyclic groups, additional quaternary ammonium atoms, and additional amide or alkylol groups. Q may be further substituted with OH, Y, and the like, where Y is a halogen atom.

Included within the contemplated scope of Q are:

where R R and R, can be aliphatic hydrocarbon radicals of from one to 24 carbon atoms or R is a divalent aliphatic radical of from one to 10 carbon atoms, and X is as above. Compounds in which R and R are both derived from fatty acids and are thus aliphatic hydrocarbon radicals having from 8 to 22 carbon atoms are particularly desirable.

Compounds of the present invention are prepared via the reaction of an amide containing quaternary ammonium where Q, R R, R", R', and X are as described above, and where the aldehydes suitable for reaction with the amide-containing quaternaries are: formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, and the like. This reaction is carried out generally in aqueous solution just prior to use of the material to impregnate cloth. However, the alkylol derivative may be prepared separately, isolated, and the isolated compound used in impregnate cloth from a suitable solution. Reaction with formaldehyde is the preferred embodiment of our invention. The reaction proceeds smoothly. Formaldehyde is readily available and inexpensive. The reaction products are particu- 0 larly effective.

Impregnation of the cotton article is generally carried out from an aqueous system by soaking, dipping, padding, spraying, or some other suitable means of contacting the article with the treating chemical. This impregnation step is not limited to water solutions. Any solvent system in which the derivative is sufficiently soluble and with pregnation of cotton fabric at a level of about 0.3% nitrogen, said nitrogen deriving from the absorption thereon of the methylol derivative, drying the cotton fabric, and curing at 140 C. for 10 minutes.

The amide-containing quaternary ammonium compounds useful as starting materials to react with aldehydes to form the alkylol derivatives which constitute the permanent sanitizing agents of the present invention can be prepared by a number of methods. Representative of these methods are the following:

(A) PREPARATION OF QUATERNARIES DERIVED FROM THE REACTION OF TERTIARY AMINES AND HALO-AMIDES more specifically:

Cr2II25N(CH3)z ClCIIzCONHa [CmHzsNHCHghCHzCONHflCl This preparation is illustrated as follows: Equipment consisted of 3-liter 3-neck round-bottom flask equipped with a thermometer, stirrer, and reflux condenser. The reaction schedule was as follows:

To a charge of 410 g. of lauryl dimethyl amine (2 moles) in 420 g. of isopropanol:

Analysis (percent) Heating, Time Amine Free Step CICH CONH NaHCO; C.) On.) HCI amine 1 206 g. (2.4 moles) 31 g. in 62 11,0 to 70 g Reflux 1 4.213 1 1 O 1 4. 5 4 25.5 80 2.9 0.0 5 12g 24g s0 1 0.0 2. 7

which the derivative does not react, e.g., alcohols, alcohol/ water, ketones, ketone/water, chlorinated solvents, dimethylsulfoxide, dimethylformamide, and the like would be generally suitable. Generally after impregnation, the cotton article is dried and then cured to fix the derivative on the cotton fiber. Curing is at elevated temperatures, in the range of 80 C. to 150 C., and preferably in the range of 100 C. to 150 C. Temperatures appreciably higher than 150 C. would usually result in scorching or discoloring of the cloth. Lower temperatures would require prolonged periods to effect cure, The time of curing may vary over a fairly wide range, generally of the order of a few minutes to an hour depending in part on the temperature.

The amount of derivative bound to the article is a function of the concentration of the impregnating bath, the period of exhaustion, the solution hold-up in the article, whether or not the article was rinsed and how long rinsing was carried out, and the specific affinity of the particular quaternary ammonium grouping for the surface of the cellulosic fiber. A wide range of treatment levels are suitable for the purposes of this invention. The level of treatment may be determined in a number of Ways. We have found a convenient method of determination to be a determination of the nitrogen content of the treated article. In general, nitrogen levels of about 0.01% to about 1.0% by weight are applicable, but these levels are preferably in the range of about 0.1 to 0.5% by weight.

A preferred embodiment of the present invention is demonstrated by the preparation of the methoylol derivative of an N-fatty N,N-dimethyl acetamide quaternary ammonium chloride via reaction with formaldehyde:

in which R is an aliphatic hydrocarbon radical of a fatty acid and contains from 8 to 22 carbon atoms, the im- The final product was recovered by filtration and had the following analyses:

Percent Sodium chloride 0.3

Quaternary chloride 55.5

Free tertiary amine 6.2 Amine hydrochloride 0.1 Ionic chloride 6.6

Water 4.7 Total volatiles 39.8

(B) PREPARATION OF THE ALKYL HALIDE QUA- TERNARIES OF DIALKYL AMINOHYDROXY- STEARAMIDES This preparation is illustrated as follows: A reaction autoclave was charged with 277 g. of dimethylaminohy droxystearamide, 267 g. isopropanol and 42 g. of sodium bicarbonate. To this was attached a methyl chloride cylinder, and a methyl chloride atmosphere maintained above the reaction mixture. The run proceeded as follows:

At the end of the 4 /2 hours, the system was cooled, vented, and the product recovered by filtering off the NaHCO The final product analyses:

Percent Quaternary 49 Free tertiary amine 1.84 Ironic chloride 4.45 Volatile material 57.7

(C) PREPARATION OF THE ALKYLOL DERIVATIVES The alkylol derivatives which are the specific fabric treatment compositions of the present invention are prepared via the reaction of an amide grouping with an aldehyde.

I, CONHR" OHOR'" OONCHOH more specifically where melted (at about 50 C.). A solution of 6 grams of K CO in 22.5 ml. 40% formaldehyde (140% excess) and 75 ml. water was added and the mixture was kept at 65 C. for 10 minutes. More water was added till the volume was 500 ml., and the mixture was cooled to 40 C., at which temperature oxalic acid was added till pH 2.2. The volume was made up to 600 ml. by the addition of water.

This solution contained theoretically 17.5% of the methylol compound. The material precipitated on cooling to room temperature. Therefore, all impregnations were carried out at about 60 C.

(3) To 386 grams (209 grams of active quaternary) of a compound, prepared in a manner analogous to A above having the formula (derived from the quaternization of dimethyl hydrogenated tallow amine with chloroacetamide) and having the following analyses:

Solvent: a mixture of isopropanol and water.

1 Theoretically 5.1% for CzzHnONCl.

A solution was added of 5 grams potassium carbonate and 45 ml. of a 40% aqueous solution of formaldehyde in 300 ml. water. The mixture was heated for 10 minutes at 70 C. The solution was cooled and acidified with a concentrated solution of oxalic acid to pH 2.5 and diluted with water to 750 ml. This solution theoretically contained about 30% of the methylol compound.

(D) IMPREGNATION OF THE CLOTH Generally the impregnation of the cellulosic material is accomplished by application from an aqueous solvent, drying, and curing.

The impregnation may be illustrated as follows:

Fabric samples (7.5 m. x 17 cm.) were impregnated on a three-bowl laboratory padding machine (two dips, two nips) at a velocity of about 8 m./min. The impregnating solutions were those of D1 and D2 above and appropriate dilutions thereof. Drying of the impregnated cloth was carried out in a specially designed forced draft oven. The cloth was led through continuously at a constant speed. Drying conditions: 10 minutes at 75 C.:1

After drying as above, where chemical bonding of the derivative to the cloth was desired, the fabric samples were cured in the same oven. Curing conditions: 10 minutes at 140 C.i2. After curing, unreacted material was removed by rinsing the cured fabric samples thoroughly with hot and cold water, and when it appeared that an additional extraction with ethanol gave a further decrease in nitrogen content, all samples were extracted with hot ethanol in an extraction apparatus. The amount of unreacted material in the extracted samples appeared to be quite low.

(E) BIOLOGICAL TESTING PROCEDURES FOR IMPREGNATED FABRIC SAMPLES The fabric samples prepared above were subjected to (a) burial tests, (b) zone of inhibition tests, and (c) respiratory inhibition tests. In addition, the effect of prolonged leaching (24 hours running tap water at 29 C i 0.5 on the performance of the samples in the above tests was determined. This leaching was executed in accordance with method 5830 (15-5-1951) from the Federal Specification CCC-T-l91b (Leaching resistance of cloth; Standard method).

(a) Soil burial tests for rot and mildew were according to: method 5F62 (15-5-1951) from the Federal Specification CCC-T-191b (Mildew resistance of cloth; Soil Burial method): v

Strips of samples (not leached and leached) were buried in soil, composed of equal parts of good leaf mould, wellrotted and shredded manure, and coarse sand. The soil was kept at a temperature of 30 C. 1 05 C. The moisture content was 27% of the dry weight. After incubation periods of two and four weeks, the strips were cleaned, dried, conditioned and finally tested for their tensile strengths, unexposed strips being used as controls.

(b) Zone of inhibition tests (agar plate method) were in accordance with tentative A.A.T.C.C.Test Method (1958) Detection of Anti-Bacterial Property of Fabrics, Agar Plate Method.

Test organisms were: Staphylococcus aureus Rosenb. 1884 (Micrococcus pyogenus var. aureus) strain ATCC 6538 and Escherichia coli (Migula, 1895), Castellani and Chalmers 1919 strain ATCC 11229.

The test specimens were incubated for 24 hours at 37 C. 1 0 5 C. The zone of inhibition (halo) was given in mm., and the contact areas were examined by means of a microscope.

(0) Respiratory inhibition by the Warburg method was determined as follows:

The respiratory inhibition produced by the compounds tested was measured by the Warburg method. Fabric samples containing the chemically bound methylol derivative and samples treated only with the amide-containing quaternaries were tested, both leached and unleached.

The bacteria were grown in Nutrient Broth (Difco B3) for 24 hours. After this time, the cells were centrifuged, washed with distilled water, and once more centrifuged.

The cells were suspended in buffer solution pH 6.8 (4.35 g. K HPO and 3.40 g. KH PO in 1000 ml. distilled water).

Each Warburg vessel contained a fabric sample, 1 ml. of a bacterium suspension and 0.5 ml. 10% glucose solution. The cup in the center of the vessel contained 0.2 ml. 20% KOH solution and some filter paper to absorb the CO After 20 minutes, shaking, the readings started. The time of measurement was 90 minutes.

The inhibition of the respiration was calculated with the following formula:

Vo-V

R=inhibition (percent) Vo=respiration in mm. 0 on the untreated samples after 60 minutes. V=respiration in mm. 0 on the treated samples after 60 minutes.

The bacteria were the same as in E, (b) above. The following examples will serve to illustrate the specific embodiments of the present invention. These examples are illustrative only and not to be considered as limiting the scope of our invention.

Example I Using the procedures (A), (C) (l), and (E) described above, the methylol derivative of was prepared and cotton fabric samples impregnated therewith were prepared.

Example II Using the procedures (B), (C) (2), and (E) described above, the methylol derivative of was prepared and cotton fabric samples inpregnated therewith were prepared.

Example III The impregnated cotton fabrics of Examples I and II above were tested using the biological testing procedures of (E) above. The results are summarized in Table I.

Example 1V Using the procedures (A), (C) (3), and (E) described above, the methylol derivative of TABLE I.SUl\l'M.ARY OF BIOLOGICAL TESTING [Examples I and II] Soil burial, retention of tensile strength 1 Cone. of Non-leached 3 Leached 4 impregnating bath, Percent Not Buried Buried Not Buried Buried Samples 1 percent N 2 buried 2 wks. 4 wks. buried 2 wks. 4 wks. Example 1.. 30 0. 35. 4 36.0 33. 6 35. 8 33. 8 34. 5 Do 4 0.24 52. 1 47. 2 20. 6 52. 3 28.1 5. 3 130-.-. 10 0. 28 47. 9 40. 0 45. 5 46. 9 42. 6 40.4 Example II- 5 0.43 50. 9 47. 5 37. 2 49. 1 48. 9 43. 5 Do .8 0. 26 62. 4 45. 7 9. 7 52. 2 46.0 23. 3 Do .0 0. 18 55.0 21. 3 5. 6 48. 9 12.1 1. 3 Control 35. 6 0 0 Cu-naphthenate- 42. 5 41. 5 40. 6 Hexachlorophene Respiratory inhibition, Zone of inhibition, agar plate method Warburg method Halo, in mm. Growth under sample Inhibition (R) Before After Before After Before After leaching 3 leaching 3 leaching I leaching 4 leaching 3 leaching 4 E. S. E. S. E. S. E. E. S. E. S:

Sample 1 eoli aureus coll aureus coll aureus eoli aureus coll aureus coli aureus Example I 0 3. 2 0 0 :l: 0 20 8 D0. 0.8 7.0 0 0 43 100 8 18 Do 0.5 5. 3 0 0.1 36 100 0 6 Example II- 0 3. 2 0 0. 4 :1: 0 100 22 66 Do 0 4. 3 0 0.4 36 20 0 0 Do- 0 3. 7 0 0 26 0 27 0 Control 0 0 0 0 Cu-naphthenate. Not investigated Hexaehlorophene 2. 2 3. 7 0 3. 7

1 2.5 cm. strips, 15 cm. between jaws, velocity at 10 emJmin a As prepared.

1 Percent N as measured on the impregnated, cured and rinsed fabric sample.

4 24 hours in running tap water at 29 C.

TABLE II.SUMMARY OF BIOLOGICAL TESTING Respiratory inhibition, Warburg method Inhibition (R) S011 burial, retention of tenslle strength 1 Before After Cone. of N on-leached 3 Leeched 4 leaching 3 leaching 4 impregnating bath, Percent Not Buried Buried N t Buried Buried E. S. E. S. Sample 2 percent N 2 buried 2 wks. 4 wks. buried 2 wks. 4 wks. coli aureus coli aureus 30 0. 29 26. 7 37. 6 39. 39. 7 39. 0 40. 8 0 67 0 66 0. 22 61. 4 56. 8 46. 2 56. 8 52. 2 45. 2 56 87 5 77 3 0. l6 g 58. g 55. 0 59. 8 56. 9 46. 2 58 100 36 100 Cu-naphthenate. 58: 3 61. 4 e

1 2.5 cm. strips, cm. between jaws, velocity at 10 cm./min. 3 As prepared. 1 Percent N as measured on the impregnated, cured and rinsed fabric 4 24 hours in running tap water at 29 C. samp e.

Example V OH H To determine the efiicacy of the methylol derivative oliicfl oinxin creating a permanent bond to the cellulosic fabric N Ha)s and to show that this bond does not mater1ally decrease the biocidal activity of the quaternary ammonium group, h i i a l f in anion a Serles of cotton cloths were treated as Examples I 2. The process of treating cellulosic articles comprising and L except that the amide-Containing the absorption onto the cellulosic article a solution of quaternary compound was utlllzed instead of the corresponding methylol derivative, and with the exception that no cure step was employed since there was no active c11 or{,) 0Ir0Ir- 0Hr) -CONCHrOH1X- group to bond to the cotton. These were then tested in a no Nflcnm soil burial test. Results are given in the following 0 Table III. wherein X" is a salt forming anion.

TABLE III Soil burial, retention of tensile strength 1 Non-leached 3 Leeched 4 Buried 2 Buried 4 Not buried Buried 2 Buried 4 Sample Percent N 2 Not buried wks. wks. wks. wks wks.

[C12H25N(CH3)2CH2C ONHAOI- 0. 49 47. 4 46. 5 40.1 49. s 0 0 Same as above- 0.42 47. 1 41. 9 13. 2 47.8 0 0 Do 0.36 49. 3 43. 4 18.5 47. 1 0 0 (3H CH2(CH2)1CHCH(CH2)7CONH2 0.47 48.0 26.8 0.9 49.! 1.3 0

Same as above 0. 42 48. 3 21.1 2.0 47. 5 0

2.5 cm. strips, 15 cm. between jaws, velocity at 10 cmJmin. 3 As prepared. 1 Percent N as measured on the impregnated, cured and rinsed fabric 4 24 hours in running tap water at 29 C. samp e.

A comparison of the above data with that of Example References Cited III shows quite clearly that the overall effectiveness of UNITED STATES PATENTS the bound (cured) methylol derivative is significantly 2 203 92 6 1 40 l 8 1163 X greater than that of the unbound amide-containing 336 179 12; 134 Evan;L et a -167. 22 quaternary. Leaching has a marked deleterious effect on 08,851 1/ -1 P the unbound material, thus demonstrating clearly the 1 19 eltsc 6 et a the mud firmed by the methyl NORMAN G. TORCHIN, Primary Examiner.

The embodiments of the invention in which an ex- J. CANNON, Assistant Examiner. elusive property or privilege is claimed are defined as follows: US. Cl. X.R.

1. A process of treating cellulosic articles comprising 167 22, 3&6; 8 100, 1163; 117 138 5 the impregnation of the cellulosic article with a solution of UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,453,067 July 1 1969 Cornelis van Bochove et a1 It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, lines 3 to 8 the indistinct portion of the formula should read H O lines 70 to 73, that portion of the formula reading CH CH I 3+ should read s I 3+ RN RI? Column 4, lines 60 to 70 that portion of; the formula reading N l N should read CH CH CH CH3" Column 5 line 35 after "above" insert the following formula:

u [C H N(CH CH CONH JCJ Columns 7 and 8, TABLE I lower portion, thirteenth column, line 1 thereof, "8" should read 82 Columns 9 and 10 TABLE II first column, line 1 thereof, "Example" should read Example IV same table, fourth column, line 1 thereof, "26 7" should read 36 7 TABLE III under the heading "Sample" that portion of the first formula reading [C H N" should read [C H N under the same heading, that portion of the second formula reading "CHZTCH J should read CH (CH same TABLE III sixth column, line 5 thereof, "47 5" should read 47 .4 same table eighth column, line 5 insert 0 Signed and sealed this 5th day of May 1970 (SEAL) Attest:

EDWARD M. PLETCHER,JR. I WILLIAM E. SCHUYLER, JR. Attesting Officer Commissioner of Patents 

1. A PROCESS OF TREATING CELLULOSIC ARTICLES COMPRISING THE IMPREGNATION OF THE CELLULOSIC ARTICLE WITH A SOLUTION OF 